Replication of flexible polymer membranes with geometry-controllable nano-apertures via a hierarchical mould-based dewetting

Abstract

Membranes with nano-apertures are versatile templates that possess a wide range of electronic, optical and biomedical applications. However, such membranes have been limited to silicon-based inorganic materials to utilize standard semiconductor processes. Here we report a new type of flexible and free-standing polymeric membrane with nano-apertures by exploiting high-wettability difference and geometrical reinforcement via multiscale, multilevel architecture. In the method, polymeric membranes with various pore sizes (50-800 nm) and shapes (dots, lines) are fabricated by a hierarchical mould-based dewetting of ultravioletcurable resins. In particular, the nano-pores are monolithically integrated on a two-level hierarchical supporting layer, allowing for the rapid (o5 min) and robust formation of multiscale and multilevel nano-apertures over large areas (2 Â 2 cm 2 ).

Multiplex lithography for multilevel multiscale architectures and its application to polymer electrolyte membrane fuel cell

“…As a thin Nafion membrane is often fragile during the catalyst-coating process ( Supplementary Fig. 12 ), L 1 provides a geometrical reinforcement from the hierarchical levelling of relatively thin areas with a thickness of L 2 (∼30 μm) and L 3 (∼10 μm) 18 . In this way, both regions ( L 2 and L 3 ) affected the reduced membrane resistance, while the region of L 1 ensured mechanical robustness.…”

“…Complex hierarchical microarchitectures have emerged 17 to overcome engineering issues arisen from a single scale 18 19 20 . However, the production of complex multilevel and multiscale architectures with soft materials remains challenging, mainly because soft lithography basically employs sufficient thermal or ultraviolet treatments to fully solidify the raw materials for high pattern fidelity 14 21 22 23 24 .…”

Recent Advances in Unconventional Lithography for Challenging 3D Hierarchical Structures and Their Applications

“…Cho et al [107] created a new type of flexible, mechanically stable, and free standing polymeric membrane by using a hierarchical mold-based CFL. As shown in Figures 3(g) and 3(h), the robust membrane with three-level hierarchical apertures (800 m/20 m/500 nm) was well defined without structure collapses or defects over a large area.…”

Investigation of Structural Stability for Monolithic Nano Bridges on Micro Apertures

“…However, an implementation of polymeric flexible materials has its benefits, such as inducing folding/crumpling phenomena during the fabrication process, which leads to a limit in the aperture size and thickness [9,10]. To address these issues, a polymeric nano-aperture membrane monolithically constructed on a supporting layer with micro-apertures was reported previously [11,12]. The one-step process based on the scavenging effect of the infiltrated oxygen gas is highly advantageous in the facile fabrication of free-standing membranes with nano/micro two-level apertures.…”